Pyrazine odour makes visually conspicuous prey aversive

Unpalatable insects frequently adopt multimodal signals to ward off predators, incorporating sounds and odours into their colourful displays. Pyrazine is an odour commonly used in insect warning displays, and has previously been shown to elicit unlearned biases against common warning colours, e.g. yellow and red in naive predators. We designed two experiments to test for similar effects of pyrazine on the conspicuousness of prey, perhaps the most ubiquitous aspect of aposematic coloration. In the first experiment, we offered predators (Gallus gallus domesticus) a choice between conspicuous crumbs and cryptic crumbs in the presence or absence of pyrazine. In the second experiment, we manipulated the birds' experience of conspicuous prey during an initial training phase. Only in the presence of pyrazine did birds show a bias against conspicuously coloured food, and this occurred whether or not they had previously experienced food that contrasted with the background. This emergent behaviour relied upon the visual and odorous signal components being presented together. These unlearned, yet hidden, responses against conspicuousness demonstrate that there are initial benefits to prey being conspicuous when the multimodal nature of warning signals is accounted for.

Regional cerebral blood flow in fibromyalgia: single-photon-emission computed tomography evidence of reduction in the pontine tegmentum and thalami

OBJECTIVE

To determine whether regional cerebral blood flow (rCBF) is abnormal in any cerebral structure of women with fibromyalgia (FM), following a report that rCBF is reduced in the thalami and heads of caudate nuclei in FM.

METHODS

Seventeen women with FM and 22 healthy women had a resting single-photon-emission computed tomography (SPECT) brain scan to assess rCBF and a T1-weighted magnetic resonance imaging (MRI) scan to enable precise anatomic localization. Additionally, all participants underwent 2 manual tender point examinations and completed a set of questionnaires evaluating clinical features. SPECT scans were analyzed for differences in rCBF between groups using statistical parametric mapping (SPM) and regions of interest (ROIs) manually drawn on coregistered MRI.

RESULTS

Compared with control subjects, the rCBF in FM patients was significantly reduced in the right thalamus (P = 0.006), but not in the left thalamus or head of either caudate nucleus. SPM analysis indicated a statistically significant reduction in rCBF in the inferior pontine tegmentum (corrected P = 0.006 at the cluster level and corrected P = 0.023 for voxel of maximal significance), with consistent findings from ROI analysis (P = 0.003). SPM also detected a reduction in rCBF on the perimeter of the right lentiform nucleus. No correlations were found with clinical features or indices of pain threshold.

CONCLUSION

Our finding of a reduction in thalamic rCBF is consistent with findings of functional brain imaging studies of other chronic clinical pain syndromes, while our finding of reduced pontine tegmental rCBF is new. The pathophysiologic significance of these changes in FM remains to be elucidated.

Specificity of preformed alloantibodies causing B cell positive flow crossmatch in renal transplantation

The specificity of alloantibodies (alloAb) and their clinical significance in association with T-/B+ flow cytometry crossmatch (FCXM) in kidney transplantation are not clearly defined. This study was undertaken to examine the HLA specificity and clinical relevance of Ab causing B+ FCXM in pre-transplant (final XM) recipients' serum samples. Final FCXM serum samples were analyzed from 457 renal transplant patients followed for 10 months post-transplantation. Two hundred and sixty patients had T-/B+ final FCXM. The control group included 197 recipients with T-/B- FCXM at time of transplantation. Class I/class II PRA and specificity of anti-HLA class I and class II Ab in final FCXM serum samples were analyzed by FlowPRA Class I Screening Test and FlowPRA Class II Screening Test. We found no correlation between graft outcome and pre-transplant T-/B- and T-/B+ FCXM status. Additionally, we observed no clinical relevance of B+ FCXM in retransplant patients. However, MCS > or =200 in B+ FCXM retransplant recipients was associated with anti-class II Ab to previous mismatches in regrafted patients (n = 46). This finding was confirmed by specificity analysis of anti-DR/DQ Ab in patients with high ( > or =15%) class II PRA. In 63% (12 of 19) of retransplants having T-/B+ FCXM, we defined the specificity of alloAb to first graft mismatched class II antigens. In contrast, anti-class II Ab was detected in only 5.7% (2 of 35) of single-graft recipients with different PRA values. Significantly greater MCS (240 +/- 61 vs. 163 +/- 48; p = 0.022) was observed in retransplant patients having short ( < or =5 m) previous graft survival time (PGST) than in those with long PGST ( > or =5 m). Only 2% of retransplant recipients with B + FCXM had non-HLA Ab. In contrast, the overwhelming majority of primary recipients had no detectable alloAbs. No significant difference in class I PRA was found between B- and B+ FCXM recipients. However, class II PRA was significantly higher in patients having B + FCXM (p = 0.028). Collectively, these data show that MCS intensity is not always a reliable criterion for anti-HLA Ab detection because of the presence of non-HLA Ab. These results can be explained by low titers of anti-class II Ab, at which concentration these Ab cannot produce a deleterious effect. FlowPRA and Flow screen beads appeared to be reliable and sensitive methods for detection and specificity analysis of anti-class II alloAb.

Toward a developmental family therapy: the clinical utility of research on adolescence

Tremendous advances have been made in our understanding of the intrapersonal, interpersonal, familial, and contextual characteristics and processes that contribute to adaptive as well as maladaptive developmental outcomes with high-risk and clinically referred adolescents. This empirical knowledge base offers clinically rich opportunities for systematic treatment development. An important step in this process is distinguishing which research findings in basic science areas such as developmental psychology and developmental psychopathology might have clinical relevance. Toward this goal, we review relevant but selective research in areas that are central to clinical work with adolescents (parent-adolescent relationship, biological aspects, and affect and cognition), and we offer examples of how basic research in these areas can inform treatment.

Validation of fully automatic brain SPET to MR co-registration

Fully automatic co-registration of functional to anatomical brain images using information intrinsic to the scans has been validated in a clinical setting for positron emission tomography (PET), but not for single-photon emission tomography (SPET). In this paper we evaluate technetium-99m hexamethylpropylene amine oxime to magnetic resonance (MR) co-registration for five fully automatic methods. We attached six small fiducial markers, visible in both SPET and MR, to the skin of 13 subjects. No increase in the radius of SPET acquisition was necessary. Distortion of the fiducial marker distribution observed in the SPET and MR studies was characterised by a measure independent of registration and three subjects were excluded on the basis of excessive distortion. The location of each fiducial marker was determined in each modality to sub-pixel precision and the inter-modality distance was averaged over all markers to give a fiducial registration error (FRE). The component of FRE excluding the variability inherent in the validation method was estimated by computing the error transformation between the arrays of MR marker locations and registered SPET marker locations. When applied to the fiducial marker locations this yielded the surface registration error (SRE), and when applied to a representative set of locations within the brain it yielded the intrinsic registration error (IRE). For the best method, mean IRE was 1.2 mm, SRE 1.5 mm and FRE 2.4 mm (with corresponding maxima of 3.3, 4.3 and 5.0 mm). All methods yielded a mean IRE <3 mm. The accuracy of the most accurate fully automatic SPET to MR co-registration was comparable with that published for PET to MR. With high standards of calibration and instrumentation, intra-subject cerebral SPET to MR registration accuracy of <2 mm is attainable.

Safety-net health plans: a status report

This paper reports on a national survey of Medicaid managed care plans sponsored by safety-net provider organizations that have a mission of service to low-income populations. We identified ninety-nine safety-net plans and obtained data from eighty of them regarding their sponsorship, age and size, relationships to sponsors, managed care practices, and measures of success. Most plans engage in active managed care and have achieved at least some of their goals. However, 60 percent of plans lost money in 1997, and economic trends have been unfavorable.

Receiver psychology and the evolution of multicomponent signals

Many animals produce and respond to signals made up of multiple components. For example, many avian sexual displays are highly extravagant combinations of visual and acoustic elements, and are described as being 'multicomponent'. One possible reason for the evolution of such complex signals is that they provide more reliable information for receivers. However, receivers also influence signal evolution in another important way, by how they perceive and process signals: signallers will be selected to produce signals that are more easily received. The potential role of receiver psychology in the evolution of multicomponent signals has not previously been considered; in this review I present psychological results that support the notion that two components are better received than one alone. Detection can be improved by producing two components together, thus reducing the reaction time, increasing the probability of detection and lowering the intensity at which detection occurs. Discriminability of multicomponent stimuli is also made easier through better recognition, faster discrimination learning and multidimensional generalization. In addition, multicomponent stimuli also improve associative learning. I show that multicomponency does indeed improve signal reception in receivers, although the benefits of producing components in two sensory modalities (bimodal multicomponent signals) may be larger and more robust than producing them in just one (unimodal multicomponent signals). This highlights the need for consideration of receiver psychology in the evolution of multicomponent signals, and suggests that where signal components do not appear to be informative, they may instead be performing an important psychological function. Copyright 1999 The Association for the Study of Animal Behaviour.

Mental health services in the county jail: a critical partnership?

This study was designed to provide a description of individuals incarcerated in a county jail and referred for mental health services. A standardized intake form was completed for 598 inmates who had contact with the mental health counselor. Analysis of the mental health status of inmates suggests that the presence of a counselor in the jail may serve an important function. Specifically, inmates referred to the counselor were not in acute distress. This suggests they may be better served by an on-site counselor rather than through the traditional method of being transported to the hospital emergency room or community mental health center for evaluation.

Novelty effects in a multimodal warning signal

The warning signals of toxic insects are often 'multimodal', combining bright coloration with sounds or odours (or both). Pyrazine (a common insect warning odour) can elicit an intrinsic avoidance in domestic chicks Gallus gallus domesticus, both against novel coloured food, and also against food colours that are specifically associated with aposematism, namely yellow and red. In three experiments, we investigated the role of novelty in this innate bias against yellow coloured food in the presence of pyrazine. Naive chicks were familiarized either to pyrazine odour or to coloured food before being tested for a bias against yellow (warningly coloured) food as opposed to green (nonwarningly coloured) food. In experiment 1, pyrazine novelty was shown to be vital for eliciting a bias against yellow food. However, experiment 2 suggested that colour novelty was not important: chicks familiarized with coloured crumbs still avoided yellow crumbs when pyrazine was presented. In a third experiment that gave chicks an even greater degree of pre-exposure to coloured crumbs, the bias against yellow food eventually waned, although pyrazine continued to elicit an aversion to yellow even after birds had had experience of up to 24 palatable yellow crumbs. Pyrazine novelty has been an important pressure in the evolution of multimodal warning signals, and can continue to promote the avoidance of warningly coloured food, even when it is relatively familiar. The implications for warning signals are discussed. Copyright 1999 The Association for the Study of Animal Behaviour.

Errors by paediatric residents in calculating drug doses

BACKGROUND

Errors in calculating drug doses in infants and small children can cause morbidity and mortality, especially with agents exhibiting a narrow therapeutic window. A previous study from this institution has detected potential life threatening errors in calculations performed by trainees while writing prescriptions.

OBJECTIVES

To verify whether the true incidence of trainees' errors in prescribing can be explained by impaired calculation skills in written tests.

SETTING

A tertiary paediatric hospital; educational rounds for core paediatric residents.

METHODS

Two anonymous written tests, which included calculations of doses similar to those performed at the paediatric bedside; one was conducted in 1993 and one in 1995.

RESULTS

Thirty four paediatric residents participated in 1993 and 30 in 1995. A substantial number of trainees in both years committed at least one error. In general, there was no correlation between the length of training (0 to 4 years) and likelihood of making a mistake. Three trainees in 1993 and four in 1995 committed 10-fold errors. These seven residents committed significantly more errors than the rest of the group in each of the tests separately. All seven were in their first two years of training, and six were in their first year of residency.

CONCLUSIONS

A substantial proportion of paediatric trainees make mistakes while calculating drug doses under optimal test conditions. Some trainees commit 10-fold errors, which may be life threatening. The results of these anonymous tests suggest that testing of calculations skills should be mandatory, and appropriate remedial steps should follow to prevent paediatric patients receiving wrong drug dosages.

HIV-positive women living in the metropolitan Toronto area: their experiences and perceptions related to HIV testing. The HIV Women's Study Group

Forty HIV-positive women from diverse socioeconomic backgrounds were interviewed. Most (90%) did not perceive themselves to be at risk of HIV infection prior to knowing their HIV-positive status. The majority (61%) were tested because they developed symptoms, or because someone with whom they were intimate, or their child, tested positive for HIV or became ill. The majority (93%) of the women interviewed indicated that they did not receive both pre- and post-test counselling. The findings from this study suggest that encouraging individuals to be tested if they have engaged in "at risk" activities will not be appropriate for individuals who have no perception of risk, and other strategies to encourage appropriate testing may be needed. This research also suggests that continued emphasis needs to be placed on the counselling process, and that consideration may need to be given to multiple counselling sessions to ensure individuals clearly understand the information provided.

HIV-positive women living in the metropolitan Toronto area: their experiences and perceptions related to HIV testing. The HIV Women's Study Group

Forty HIV-positive women from diverse socioeconomic backgrounds were interviewed. Most (90%) did not perceive themselves to be at risk of HIV infection prior to knowing their HIV-positive status. The majority (61%) were tested because they developed symptoms, or because someone with whom they were intimate, or their child, tested positive for HIV or became ill. The majority (93%) of the women interviewed indicated that they did not receive both pre- and post-test counselling. The findings from this study suggest that encouraging individuals to be tested if they have engaged in "at risk" activities will not be appropriate for individuals who have no perception of risk, and other strategies to encourage appropriate testing may be needed. This research also suggests that continued emphasis needs to be placed on the counselling process, and that consideration may need to be given to multiple counselling sessions to ensure individuals clearly understand the information provided.

Comparison of oxygen uptake during a conventional treadmill test and the shuttle walking test in chronic airflow limitation

The purpose of this study was to investigate the relationship between performance on the shuttle walking test and maximal oxygen uptake (VO2max) during a conventional treadmill test in patients with chronic airflow limitation. Two different techniques were used to measure oxygen consumption, i.e. conventional Douglas bag techniques (treadmill test) and a portable oxygen consumption meter (shuttle test). Initially, 19 patients performed a shuttle walking test (after one practice walk) and a maximal treadmill walking test, in a randomized, balanced design. Subsequently, 10 patients, (after one practice) completed an unencumbered shuttle walking test and one supporting the portable oxygen consumption meter, in random order. The results of the first experiment revealed a strong relationship between performance during the shuttle walking test and VO2max during the treadmill walking test (r = 0.88). The results of the second experiment consistently demonstrated an incremental increase in oxygen consumption and ventilation in response to the increasing intensity of the shuttle walking test. Again, a strong relationship between VO2max and performance on the shuttle test was demonstrated (r = 0.81). We concluded that the shuttle walking test is a valid field exercise test of functional capacity. Performance on the test relates strongly to VO2max, the traditional indicator of cardiorespiratory capacity.

Comparison of oxygen uptake during a conventional treadmill test and the shuttle walking test in chronic airflow limitation

The purpose of this study was to investigate the relationship between performance on the shuttle walking test and maximal oxygen uptake (VO2max) during a conventional treadmill test in patients with chronic airflow limitation. Two different techniques were used to measure oxygen consumption, i.e. conventional Douglas bag techniques (treadmill test) and a portable oxygen consumption meter (shuttle test). Initially, 19 patients performed a shuttle walking test (after one practice walk) and a maximal treadmill walking test, in a randomized, balanced design. Subsequently, 10 patients, (after one practice) completed an unencumbered shuttle walking test and one supporting the portable oxygen consumption meter, in random order. The results of the first experiment revealed a strong relationship between performance during the shuttle walking test and VO2max during the treadmill walking test (r = 0.88). The results of the second experiment consistently demonstrated an incremental increase in oxygen consumption and ventilation in response to the increasing intensity of the shuttle walking test. Again, a strong relationship between VO2max and performance on the shuttle test was demonstrated (r = 0.81). We concluded that the shuttle walking test is a valid field exercise test of functional capacity. Performance on the test relates strongly to VO2max, the traditional indicator of cardiorespiratory capacity.

Geropsychiatric emergency services: utilization and outcome predictors

Chart data on emergency room visits by elderly patients and a younger control group were examined in an exploratory study of utilization of psychiatric emergency services by the elderly and factors predictive of their subsequent admission to a psychiatric inpatient unit. Elderly patients had lower utilization of psychiatric services than their younger counterparts, but they were significantly more likely to be hospitalized following an emergency room visit. Dementia, the single most frequent diagnosis of the elderly patients, increased the likelihood of hospitalization only if it existed in combination with another psychiatric diagnosis. Medical comorbidity appeared to have no effect on whether the elderly patient was subsequently hospitalized.